Six months ago, they were mere Cold War trash: hundreds of small radioactive power generators scattered across the Soviet Union decades ago and largely forgotten, except when the odd lumberjack turned up with severe radiation burns. But in the aftermath of Sept. 11, these aging but potentially lethal devices are being viewed in a troubling new light: as possible components in a weapon to be used in a terrorist strike. Even more troubling, some of them have vanished. Full Story